package basic.com.liz.service.system;

import java.io.Serializable;

import javax.annotation.PostConstruct;

import org.apache.shiro.authc.AuthenticationException;
import org.apache.shiro.authc.AuthenticationInfo;
import org.apache.shiro.authc.AuthenticationToken;
import org.apache.shiro.authc.SimpleAuthenticationInfo;
import org.apache.shiro.authc.UsernamePasswordToken;
import org.apache.shiro.authc.credential.HashedCredentialsMatcher;
import org.apache.shiro.authz.AuthorizationInfo;
import org.apache.shiro.authz.SimpleAuthorizationInfo;
import org.apache.shiro.realm.AuthorizingRealm;
import org.apache.shiro.subject.PrincipalCollection;
import org.apache.shiro.util.ByteSource;
import org.springframework.beans.factory.annotation.Autowired;

import basic.com.liz.bean.entity.system.User;
import basic.com.liz.common.utils.Encodes;

import com.google.common.base.Objects;

public class ShiroDbRealm extends AuthorizingRealm
{
    
    protected AccountService accountService;
    
    @Autowired
    private ButtonService buttonService;
    
    /**
     * 认证回调函数,登录时调用.
     */
    @Override
    protected AuthenticationInfo doGetAuthenticationInfo(AuthenticationToken authcToken)
        throws AuthenticationException
    {
        UsernamePasswordToken token = (UsernamePasswordToken)authcToken;
        User user = accountService.findUserByLoginName(token.getUsername());
        if (user != null)
        {
            byte[] salt = Encodes.decodeHex(user.getSalt());
            return new SimpleAuthenticationInfo(new ShiroUser(user.getId(), user.getLoginName(), user.getName()),
                user.getPassword(), ByteSource.Util.bytes(salt), getName());
        }
        else
        {
            return null;
        }
    }
    
    /**
     * 授权查询回调函数, 进行鉴权但缓存中无用户的授权信息时调用.
     */
    @Override
    protected AuthorizationInfo doGetAuthorizationInfo(PrincipalCollection principals)
    {
        ShiroUser shiroUser = (ShiroUser)principals.getPrimaryPrincipal();
        User user = accountService.findUserByLoginName(shiroUser.loginName);
        SimpleAuthorizationInfo info = new SimpleAuthorizationInfo();
        info.addRoles(user.getRoleList());
        info.addStringPermissions(buttonService.findButtonCodesByUserId(user.getId()));
        return info;
    }
    
    /**
     * 设定Password校验的Hash算法与迭代次数.
     */
    @PostConstruct
    public void initCredentialsMatcher()
    {
        HashedCredentialsMatcher matcher = new HashedCredentialsMatcher(AccountService.HASH_ALGORITHM);
        matcher.setHashIterations(AccountService.HASH_INTERATIONS);
        
        setCredentialsMatcher(matcher);
    }
    
    @Autowired
    public void setAccountService(AccountService accountService)
    {
        this.accountService = accountService;
    }
    
    /**
     * 自定义Authentication对象，使得Subject除了携带用户的登录名外还可以携带更多信息.
     */
    public static class ShiroUser implements Serializable
    {
        private static final long serialVersionUID = -1373760761780840081L;
        
        public Long id;
        
        public String loginName;
        
        public String name;
        
        public ShiroUser(Long id, String loginName, String name)
        {
            super();
            this.id = id;
            this.loginName = loginName;
            this.name = name;
        }
        
        public Long getId()
        {
            return id;
        }
        
        public String getName()
        {
            return name;
        }
        
        public String getLoginName()
        {
            return loginName;
        }
        
        /**
         * 本函数输出将作为默认的<shiro:principal/>输出.
         */
        @Override
        public String toString()
        {
            return loginName;
        }
        
        /**
         * 重载hashCode,只计算loginName;
         */
        @Override
        public int hashCode()
        {
            return Objects.hashCode(loginName);
        }
        
        /**
         * 重载equals,只计算loginName;
         */
        @Override
        public boolean equals(Object obj)
        {
            if (this == obj)
            {
                return true;
            }
            if (obj == null)
            {
                return false;
            }
            if (getClass() != obj.getClass())
            {
                return false;
            }
            ShiroUser other = (ShiroUser)obj;
            if (loginName == null)
            {
                if (other.loginName != null)
                {
                    return false;
                }
            }
            else if (!loginName.equals(other.loginName))
            {
                return false;
            }
            return true;
        }
        
    }
}
